read in csv file

**gums** · 05-10-2007

hi

im having a bit of a problem with a task i have.

i have 2 csv files in which a list of countries and data is stored, ive managed to read the first csv into an array without a problem, the problem comes when i come to read in the second csv

what i want to do is run thru the second csv file and read in a figure from it for the corresponding countrty already stored in an array, however the country names are not all the same in the 2 files.

therefore what ive decided to do is do a strcmp on the country name and only add the data where the country and year matches, this is an example of the code i have so far

Code:

typedef struct {
	int year; // year for which data exists
	double pop; // Population that year (in millions)
	double bot;
	double botPerHead;
} Data;

typedef struct {
	char countryName[50]; // maximum length of name
	char countryCode[4]; // UN assigned 3 character country code
	Data yearlyData[11]; // max. 12 year’s data (1995 – 2006)
} Country;


int main(void)
{

	FILE *fppop;
	FILE *fpbot;
	Country countries[250];
	int i = -1;
	int dataYear;
	char input[1500];
	char *p;
	char previousName[50] = "";

	// read in pop file

	fppop = fopen("un-country-pop.csv", "r");

	if (fppop == NULL) {
		puts("Error opening file");
		exit(EXIT_FAILURE);
	}

	while (!feof(fppop)) {

		fgets(input, 1500, fppop);

		if (input[0] == '#')
			continue;

		p = strtok (input,",");

		if (strcmp(p, previousName) != 0) {
			// first time we've seen this country
			i++;
			// copy country name to countries[i].
			strcpy(previousName, p);
		}

		strcpy(countries[i].countryName, p);
		p = strtok (NULL,",");
		strcpy(countries[i].countryCode, p);
		strtok(NULL,",");
		strtok(NULL,",");
		strtok(NULL,",");
		p = strtok(NULL,","); // year string
		dataYear = atoi(p);
		countries[i].yearlyData[2006 - dataYear].year = atoi(p);
		p = strtok(NULL,","); //pop
		countries[i].yearlyData[2006 - dataYear].pop = atof(p);
	}

// read in bot file
	fpbot = fopen("un-trade-balance.csv", "r");
	if (fpbot == NULL) {
		puts("Error opening file");
		exit(EXIT_FAILURE);
	}

                i = 0;

	while (!feof(fpbot)) {

		fgets(input, 1500, fpbot);

		if (input[0] == '#')
			continue;

		p = strtok (input,",");


			if (strcmp(p, countries[i].countryName) != 0) {
			i++;
			}
			strtok(NULL,",");
			strtok(NULL,",");
			strtok(NULL,",");
			strtok(NULL,",");
			p = strtok(NULL,","); // year
			dataYear = atoi(p);
			p = strtok(NULL,","); // bop
			printf("%d\n",i);
			countries[i].yearlyData[2006 - dataYear].bot = atof(p);
	}
}

**zacs7** · 05-10-2007

Consult the FAQ regarding checking for EOF, foef() isn't the way to do it

Don't write the same thing twice, put it into a function..
Also you must fclose() the files, and int main() must return a value to the invoker, eg return 0;

**Salem** · 05-10-2007

Also, use some functions

Before you get to reading from a file, you can do this

Code:

void processLine ( char *line );
int main ( ) {
    char input[1500] = "this,is,a,test\n";
    processLine( input );
}
void processLine ( char *line ) {
    // now do all the strtok stuff here
}

When you know you can deal with one line successfully, then you can move on to

Code:

void processLine ( char *line );
int main ( ) {
    char input[1500];
    while ( fgets(input, sizeof input, fppop) != NULL ) {
        processLine( input );
    }
}
void processLine ( char *line ) {
    // now do all the strtok stuff here
}

Notice how easy it is to slide from dealing with one line in memory to reading a whole bunch of lines from a file.

**hk_mp5kpdw** · 05-10-2007

Still making this typo?

Code:

typedef struct {
    char countryName[50]; // maximum length of name
    char countryCode[4]; // UN assigned 3 character country code
    Data yearlyData[11]; // max. 12 year’s data (1995 – 2006)
} Country;

Do you mean Data yearlyData[12];?

**zacs7** · 05-10-2007

Originally Posted by hk_mp5kpdw

Still making this typo?

Code:

typedef struct {
    char countryName[50]; // maximum length of name
    char countryCode[4]; // UN assigned 3 character country code
    Data yearlyData[11]; // max. 12 year’s data (1995 – 2006)
} Country;

Do you mean Data yearlyData[12];?

But then 1995 - 2006 = 11

**hk_mp5kpdw** · 05-10-2007

Originally Posted by zacs7

But then 1995 - 2006 = 11

1995 through 2006 inclusive is 12 years.

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